This proposal is a renewal for studies of the epidemiology of, and genetic-environmental interaction in the etiology of, non-insulin dependent diabetes mellitus (NIDDM). The emergence of diabetes in the Pacific islanders has been concomitant with rapid social, economic and environmental changes. These may not be the only factors contributing to the increased rates of diabetes as there appear to be marked differences in susceptibility to NIDDM between ethnic groups in the region. The present study intends to extend this work to populations in India to provide a comparison with migrant Asian Indians in the Pacific. We intend to utilize the opportunities presented in the Pacific and India by cross- sectional and longitudinal epidemiology studies, family studies and crosscultural comparisons in a number of ethnic groups - Polynesians, Micronesians, Melanesians and Indians (migrant and those from subcontinent). The major objectives of the proposed research are: 1. To define the epidemiology and natural history of NIDDM and its complications in these populations. 2. To determine whether foreign genetic admixture influences the prevalence of NIDDM in the various ethnic groups in the Pacific. 3. To determine whether specific genetic markers exist in subjects with, or at risk of, NIDDM. 4. To determine whether there are ethnic groups protected from NIDDM and whether such protection is related to the presence of specific genetic markers, or protection from environmental, behavioural and social risk factors. 5. To establish the role of environmental risk factors e.g. diet, obesity, physical inactivity etc. in the etiology of NIDDM in these populations. 6. To define the natural history of IGT in these ethnic groups. The proposed research is of considerable interest as NIDDM may be potentially preventable. Thus, the elucidation of methods to detect "at risk" individuals, and a greater understanding of environmental precipitating factors would provide important directions for the development of prevention and control programs.